Siborg LCR-Reader-MP, Руководство пользователя

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LCR-Reader-MP Manual Siborg Systems Inc. 5
Q - Quality Factor
D - Loss Tangent
RMS - RMS value
TRMS
– True RMS Value
LF - Low Frequency
Z - Impedance
| Z | - Impedance Module
DDS - Direct Digital Frequency Synthesis
DC - DC Voltage
AC - Alternating Voltage
4 Principle of Operation
Fig. 1 shows the LCR meter block-diagram. Voltage from the voltage source through a limiting 1 kOhm
resistor is applied to the DUT connected at points A and B. The amplitude and frequency of the Test
Signal V are adjustable. It is
also possible to apply either positive or negative DC voltage to the DUT. A
voltage drop on the DUT is measured by DAu. The voltage drop on resistor Rj measured by DAj is
proportional to the current flowing through the measured component. After digitizing the ADC signals
the impedance is calculated according to the formula DUT impedance Z =Rj* Vau/Vaj.
Values of Impedance obtained during calibration with Open and Short probes are stored in the non-
volatile memory of the device and are taken into account in the calculation of the impedance of the
measured component thus eliminating the offsets due to the device internal parasitics.
The measured component can be represented in one of the following equivalent circuits:
[1] and [2]: series circuits
[3] and [4]: parallel circuits
Impedance in series circuits Z = Rs + iXs and in parallel circuits Z = 1/(1/Rp + 1/iXp) where Xs (Xp) <0
if the reactance is capacitive and at Xs (Xp) >0 the reactance is Inductive.
4.1 Formulas to Determine the Parameters:
Electrical capacitance C = 1/(2π f |Xs|) where f is the test frequency.